Fact of the case:Thomas Jefferson defeated John Adams in 1800 presidential election.Beforre jefferson took office adams congress passed the act of 1801,which created new court added mid night judges and gave the president more control over appointment of jidges.It is a attempt by Adams to frustrated his successor as he use the act to appoint 16 new circuit judge and 42 new judges.But it would not be valid until their comission was not delivered.Murbary petitioned the Supreme Court to compel the new secretary of the state to deliver his documents. 

Decision:The cout found that Madison's refusal to the Commission was illegal but did not order to to hand over it via writ of mandamus. Instead the court held that the judiciary act 1789 enabling Marbury to bring his claim was it self constitutional but the court could not issue it. Marshall reasoned that the judiciary act of 1789 conflicted with the constitution. Congress did not have the power to modify the constitution. 

Marshall established the principle of judicial review, the power to declare a law unconstitutional.